1. Field of the Invention
This invention relates to application of traction forces to human patients in connection with treatment of skeletal and connective tissue disorders.
2. Description of the Prior Art
Apparatus for treating human patients to alleviate problems in skeletal and connective tissues is disclosed in U.S. Pat. Nos. 3,033,198; 3,086,518; 3,710,787; 3,786,803; 3,835,847; 3,847,146; 3,888,243; 3,910,263 and 3,937,216.
Of greatest interest with respect to this invention are the U.S. Pat. No. 3,835,847 and U.S. Pat. No. 3,786,803. U.S. Pat. No. 3,835,847 discloses a traction force application device in which a lever allows hand adjustment of traction force applied. A knob controls a quick take-up and release mechanism with a pulley, biased by a spring, creating tension in a cord applying traction force. A lever assembly causes traction force to be maintained at a constant level once the force is selected.
U.S. Pat. No. 3,786,803 discloses a motor and gear arrangement driving a pulley to which a traction cord is attached, where the apparatus cyclically applies traction force to the patient. An eccentric wheel shifts to move a pulley assembly, bearing against a traction cord, to adjust traction force on each cycle.
Also of interest is U.S. Pat. No. 3,910,263 disclosing a traction force application device in which a pulley is movable to assure that a cord, via which traction force is applied, is oriented parallel to a piston rod applying force to the cable. Maintenance of the geometry of the cord-piston rod combination helps control the traction force.
Of lesser interest are the U.S. Pat. Nos. 3,888,243, 3,033,198 and 3,847,146 approaches. U.S. Pat. No. 3,888,243 uses fluid pressure, U.S. Pat. No. 3,847,146 uses a vacuum and U.S. Pat. No. 3,033,198 uses a weight and pulley system for applying traction force to patients. Also less relevant is U.S. Pat. No. 3,710,787, disclosing a reversible motor and gear train applying traction force to a patient. U.S. Pat. Nos. 3,086,518 and 3,937,216 disclose cylinders applying traction force to patients where hydraulic or pneumatic circuits associated with the cylinders apply pressure to a hydraulic piston.
Despite the well developed character of this art, the need remains for a highly portable traction apparatus usable by either a physician or a physiotherapist in a medical facility or even by a patient at home, allowing rapid, easy adjustment, within fine gradations, of the applied traction force by the physician, physiotherapist or patient and which can be rapidly disengaged from the patient should an emergency arise. A further need exists for traction apparatus which upon slippage of the traction harness wrapped around the patient does not result in application of large impulse force to the patient.